Bluescreening ENTIRE Sets.

In this movie I'm making,Gladiator Brothers,I need a colloseam.But I don't have enough bricks,so I'll plan to film the clip,and Bluescreen the Colliseam in in the editing process.Sounds like a plan? :?

I'm still not sure on the main plot of this movie,so this is all an idea.If it looks great,I'll keep it.It'll look like the way T did the opening scene in MG 1&2.I hope it works.